Level indicating instruments are widely used in the various construction and related trades. Most commonly used are straight edge types using a curved tube type bubble indicator or indicators and capable or reading either vertical or horizontal surfaces in one plane and in some cases an additional curved tube bubble indicator for 45.degree. angles from the horizontal.
The disadvantages in the available devices lie in the multiple readings which must be taken to plumb a vertical member such as a stud, door frame, or pipe, alternating readings on separate sides of the member at locations substantially 90.degree. from each other. In addition, no flexibility is provided in available instruments for such tasks as installing drain pipes and lines and roof-mounted rain gutters which must slope at a predetermined angle from the horizontal for optimum performance.
In other instances, it is desirable to level an object which is above the eye level of the operator. With presently available instruments, the level indicator must be viewed from a position horizontal to, or above the level indicating tube.